Obstruction Removal System

ABSTRACT

An obstruction removal system for percutaneous removal of clots or obstructions within the vascular system is disclosed. The obstruction removal system includes a multi-lumen catheter with a plurality of circulating capture devices occurring along a drive belt. The plurality of capture devices may be basket-like devices attached to the drive belt, or may be formed by integral coiled or protuberant sections of the drive belt. The circulating capture or interference devices affect removal of the clot or obstruction bit-by-bit through a series of passes.

FIELD OF THE INVENTION

The invention relates to an obstruction removal system for percutaneousremoval of clots or obstructions within the vascular system.

BACKGROUND OF THE INVENTION

A number of vascular disorders, such as stroke, pulmonary embolism,peripheral thrombosis, and atherosclerosis, are characterized byformation of occlusions that prevent normal blood flow in blood vessels.For example, an ischemic stroke is a neurological dysfunction caused bya blockage of one of the major arteries of the brain. Hemodynamicallysignificant restriction of arterial blood flow can lead to oxygendeprivation in tissue, referred to as ischemia, and can quickly lead tocell death and organ dysfunction. The brain is the organ most sensitiveto ischemia, followed by the heart, the abdominal organs, and theextremities. The brain will usually not tolerate ischemia for very longwithout massive neuron death (stroke). When treating ischemic events inthe brain, it is imperative to restore blood flow quickly and safely.The blockage can be the result of emboli or pieces of thrombotic tissuethat have dislodged from other body sites (formed in the heart, carotidartery, or elsewhere) or from the cerebral vessels themselves. Theemboli or pieces of thrombotic tissue may migrate downstream to occludein the narrow cerebral arteries. The blockage may also be caused by theformation of a blood clot at the site of blockage (thrombosis) or theobliteration of the lumen of a blood vessel caused by atherosclerosis.

Stroke is the third most common cause of death in the United States andthe most disabling neurologic disorder. Hemorrhagic stroke accounts for20% of the annual stroke population. Hemorrhagic stroke often occurs dueto rupture of an aneurysm or arteriovenous malformation bleeding intothe brain tissue, resulting in cerebral infarction. The remaining 80% ofthe stroke population are ischemic strokes and are caused by occludedvessels that deprive the brain of oxygen-carrying blood.

When a patient presents with neurological deficit, a diagnostichypothesis for the cause of stroke can be generated based on thepatient's history, a review of stroke risk factors, and a neurologicexamination. If an ischemic event is suspected, a clinician cantentatively assess whether the patient has a cardiogenic source ofemboli, large artery extracranial or intracranial disease, small arteryintraparenchymal disease, or a hematologic or other systemic disorder. Ahead CT scan is often performed to determine whether the patient hassuffered an ischemic or hemorrhagic insult. Blood would be present onthe CT scan in subarachnoid hemorrhage, intraparenchymal hematoma, orintraventricular hemorrhage.

Traditionally, emergent management of acute ischemic stroke consistedmainly of general supportive care, e.g., hydration, monitoringneurological status, blood pressure control, and/or anti-platelet oranti-coagulation therapy. In 1996, the Food and Drug Administrationapproved the use of Genentech Inc.'s thrombolytic drug, tissueplasminogen activator (t-PA) or ActivaseB, for treating acute stroke.However, the success rate of this approach is still very low. With thisform of therapy, only 30% of patients are expected to realize a good orexcellent clinical outcome several months following infusion, andpatients who demonstrate signs of intracranial hemorrhage at the time ofpresentation (on a CT study of their heads) are not candidates for t-PAtherapy. Also, intravenous t-PA therapy is associated with an almost 6%fatal intracranial hemorrhage rate.

Patients treated with t-PA were more likely to sustain a symptomaticintracerebral hemorrhage during the first 36 hours of treatment. Thefrequency of symptomatic hemorrhage increases when t-PA is administeredbeyond 3 hours from the onset of a stroke. Besides the time constraintin using t-PA in acute ischemic stroke, other contraindications includethe following: if the patient has had a previous stroke or serious headtrauma in the preceding 3 months, if the patient has a systolic bloodpressure above 185 mm Hg or diastolic blood pressure above 110 mmHg, ifthe patient requires aggressive treatment to reduce the blood pressureto the specified limits, if the patient is taking anticoagulants or hasa propensity to hemorrhage, and/or if the patient has had a recentinvasive surgical procedure. Therefore, only a small percentage ofselected stroke patients are qualified to receive t-PA.

New classes of “neuroprotectant” agents and “angiogenesis promoters” arebeing developed and tested. These drugs may extend the effectivetherapeutic window for stroke therapy and permit better long termoutcomes. Their use, however, may require novel delivery systems andoften require that the patient be stabilized and ischemia relieved inorder to obtain a lasting clinical improvement.

Obstructive emboli have also been mechanically removed from varioussites in the vasculature for years. For example, the “Fogarty catheter”or variations thereof has been used, typically in the periphery, toremove clots from arteries found in legs and in arms. These well knowndevices are described, for example, in U.S. Pat. No. 3,435,826 toFogarty and in U.S. Pat. No. 4,403,612 to Fogarty, each of which isincorporated by reference herein in its entirety. In general, thesepatents describe a balloon catheter in which a balloon material islongitudinally stretched when deflated. In procedures for removingemboli using the Fogarty catheter or other similar catheters, it istypical, first, to locate the clot using fluoroscopy. The embolectomycatheter is then inserted and directed to the clot. The distal tip ofthe balloon catheter is then carefully moved through the center of theclot. Once the balloon has passed through the distal side of the clot,the balloon is inflated. The balloon catheter is then graduallyproximally withdrawn. The balloon, in this way, acts to pull the clotproximally ahead of the balloon to a point where it can be retrieved.The majority of procedures using a Fogarty type catheter repeat thesesteps until the pertinent vessel is cleared of clot material.

A variety of alternative emboli retrieval catheters have also beendeveloped, in which various wire corkscrews and baskets must be advanceddistally through the embolic material in order to achieve capture andremoval. For example, Concentric Medical, Inc. (located in MountainView, Calif.) has created an intraluminal clot retrieval systemconsisting of a nitinol-(Nickel-Titanium alloy) shape memorycorkscrew-like coil that is advanced into an occluding clot, such asshown in U.S. Pat. No. 6,663,650; U.S. Pat. No. 6,730,104; and U.S. Pat.No. 7,285,126, each of which is incorporated by reference herein in itsentirety. The coil and its attached wire are then withdrawn from theaffected vessel, retrieving the thrombus material into a balloon-tippedguiding catheter positioned in the internal carotid artery. However,removal of emboli using such catheters carries potential problems. Onesuch problem occurs when advancing the catheter through the clotdislodges material to a more remote site where removal may become moredifficult or impossible.

New devices and methods are thus needed in treating vasculatureocclusions in the body, including treating patients with acute ischemicstroke and occlusive cerebrovascular disease, and treating symptomaticpatients with embolization or hemodynamic compromise. There are a numberof significant problems faced in designing a system which will quicklyand easily, yet effectively, evacuate emboli from a treatment locationwithin a blood vessel. First, the small size of certain vessels in whichsuch therapy occurs is a limiting factor in the design of emboli removalsystems. Vessels as small as 3 mm in diameter are quite commonly foundin the cerebral arteries, coronary arteries, and even certain saphenousvein graph bypass vessels can also be as small as 3 mm or 4 mm; althoughsome can range as high as 7 mm. Nevertheless, a successful emboliremoval system must be effective within extremely small working areasand safely traverse the tortuous cerebral vasculature. The system mustalso be equally effective in larger vessels, those of 5 mm or more indiameter.

Another obstacle is the wide variety in emboli dimensions. Althoughdefinitive studies are not available, it is believed that emboli mayhave approximate diameters ranging anywhere from tens of micrometers toa few hundred micrometers and lengths over 5 cm. More specifically,emboli that are considered dangerous to the patient may have diametersas large as 200 to 300 micrometers or even larger. Often obstructionremoval systems have only a single capture device on the distal end tocapture and contain the entire obstruction. Such a capture device mustbe of a relatively large size in order to effectively remove the entiresource of vascular occlusion in one pass. However, the relatively largesize of the single capture device may not accommodate small vessels.

Thus, an effective emboli removal system must be able to retrieverelatively large embolic particles and clots, at the same time, fitwithin relatively small vessels. In order to minimize the size of theobstruction removal system, the obstruction removal system of thepresent invention utilizes a plurality of relatively smaller capturedevices that each capture a small portion of the clot or obstruction inorder to remove the source of vascular occlusion in a piecemeal orgradual fashion.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to a system forremoving an obstruction within a body lumen. The obstruction removalsystem includes a catheter shaft and a drive belt. The catheter shafthas a proximal end, a distal end, a first lumen having a distal exitport, and a second lumen having a distal reentry port. The first andsecond lumens extend side-by-side from the proximal end to the distalend of the catheter shaft. The drive belt is disposed within thecatheter shaft in a circulating manner through the first lumen, thedistal exit port, the distal reentry port and the second lumen. Aplurality of capture devices occur along at least a portion of the drivebelt for removing the obstruction from the body lumen when the drivebelt is circulated through the catheter shaft. Each capture device iscapable of removing at least a portion of the obstruction as the capturedevice travels between the distal exit port and the distal reentry portof the catheter shaft. In one embodiment of the present invention, thedrive belt has integral sections forming the plurality of capturedevices thereon for removing the obstruction from the body lumen whenthe drive belt is circulated through the catheter shaft. In anotherembodiment of the present invention, the plurality of capture devicesare attached to the drive belt for removing the obstruction from thebody lumen when the drive belt is circulated through the catheter shaft.

Embodiments of the present invention are also directed to a method forremoving an obstruction within a body lumen. An obstruction removalsystem is positioned near the obstruction within the body lumen. Theobstruction removal system includes a catheter shaft, a drive belt, anda plurality of capture devices occurring along at least a portion of thedrive belt. The catheter shaft has a proximal end, a distal end, a firstlumen having a distal exit port, and a second lumen having a distalreentry port. The first and second lumens extend side-by-side from theproximal end to the distal end of the catheter shaft. The drive belt iscirculated though the catheter shaft such that the plurality of capturedevices are advanced through the first lumen, through the distal exitport, through the distal reentry port and through the second lumen. Atleast a portion of the obstruction from the body lumen is removed in abit-by-bit fashion as each capture device travels between the distalexit port and the distal reentry port of the catheter shaft. The entireobstruction may be removed from the body lumen after the plurality ofcapture devices are circulated through the catheter shaft in one or moreseries of passes.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following description of the invention as illustratedin the accompanying drawings. The accompanying drawings, which areincorporated herein and form a part of the specification, further serveto explain the principles of the invention and to enable a personskilled in the pertinent art to make and use the invention. The drawingsare not to scale.

FIG. 1 is a perspective of an obstruction removal system in accordancewith an embodiment of the present invention.

FIG. 2A is a cross-sectional view of an obstruction removal system inaccordance with an embodiment of the present invention taken along lineA-A of FIG. 1.

FIG. 2B is a cross-sectional view of an obstruction removal system inaccordance with another embodiment of the present invention taken alongline A-A of FIG. 1.

FIG. 3 is a sectional view of a distal portion of an obstruction removalsystem in accordance with an embodiment of the present invention.

FIG. 4 is an enlarged perspective view of a distal portion of anobstruction removal system in accordance with an embodiment of thepresent invention.

FIG. 5 is a perspective view of a capture device in accordance with anembodiment of the present invention.

FIG. 6 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 7 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 8 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 9 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 10 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 11 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 12 is a side elevational view of a wire forming a plurality ofcapture devices in accordance with an embodiment of the presentinvention.

FIG. 13 is a side elevational view of a wire forming a plurality ofcapture devices in accordance with another embodiment of the presentinvention.

FIG. 14 is a side elevational view of a wire forming a plurality ofcapture devices in accordance with another embodiment of the presentinvention.

FIG. 15 is a side elevational view of a wire forming a plurality ofcapture devices in accordance with another embodiment of the presentinvention.

FIG. 16 is a sectional view of an obstruction removal system inaccordance with another embodiment of the present invention.

FIG. 16A is a cross-sectional view of the obstruction removal systemtaken along line A-A of FIG. 16.

FIG. 17A is a perspective view of a proximal portion of an obstructionremoval system in accordance with an embodiment of the presentinvention.

FIG. 17B is a perspective view of the proximal portion of an obstructionremoval system taken along line C-C of FIG. 17A.

FIG. 18A is a perspective view of a proximal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 18B is enlarged perspective view of the proximal portion of anobstruction removal system illustrated in FIG. 18A.

FIG. 19A is a sectional view of a proximal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 19B is another sectional view of the proximal portion of anobstruction removal system illustrated in FIG. 19A.

FIG. 20A is a sectional view of a proximal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 20B is another sectional view of the proximal portion of anobstruction removal system illustrated in FIG. 20A.

FIG. 21A is a perspective view of a distal portion of an obstructionremoval system in accordance with an embodiment of the presentinvention.

FIG. 21B is a side view of the distal portion of an obstruction removalsystem illustrated in FIG. 21A.

FIG. 22A is a perspective view of a distal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 22B is a side view of the distal portion of an obstruction removalsystem illustrated in FIG. 22A.

FIG. 23A is a perspective view of a distal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 23B is a side view of the distal portion of an obstruction removalsystem illustrated in FIG. 23A.

FIG. 24A is a perspective view of a distal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 24B is a side sectional view of the distal portion of anobstruction removal system illustrated in FIG. 24A.

FIG. 25A is a perspective view of a distal portion of an obstructionremoval system including a guidewire lumen in accordance with anembodiment of the present invention.

FIG. 25B is a top view of the distal portion of an obstruction removalsystem illustrated in FIG. 25A.

FIG. 26A is a perspective view of a distal portion of an obstructionremoval system including a guidewire lumen in accordance with anotherembodiment of the present invention.

FIG. 26B is a top view of the distal portion of an obstruction removalsystem illustrated in FIG. 26A.

FIG. 27A is a perspective view of a distal portion of an obstructionremoval system including a guidewire lumen in accordance with anotherembodiment of the present invention.

FIG. 27B is a top view of the distal portion of an obstruction removalsystem illustrated in FIG. 27A.

FIG. 28A is a perspective view of a distal portion of an obstructionremoval system including a guidewire lumen in accordance with anotherembodiment of the present invention.

FIG. 28B is a side sectional view of the distal portion of anobstruction removal system illustrated in FIG. 28A.

FIG. 28C is a top view of the distal portion of an obstruction removalsystem illustrated in FIG. 28A.

FIG. 29 is a perspective view of a pulley utilized in an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 30 is a perspective view of a proximal portion of an obstructionremoval system in accordance with an embodiment of the presentinvention.

FIG. 31 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 32 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 33 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 34 is a perspective view of a capture device in accordance withanother embodiment of the present invention.

FIG. 35 is a side elevational view of a capture device in accordancewith another embodiment of the present invention.

FIG. 36 is a side elevational view of a capture device in accordancewith another embodiment of the present invention.

FIG. 37 is a side elevational view of a capture device in accordancewith another embodiment of the present invention.

FIG. 38 is a perspective view of a capture device in a straightened orunexpanded configuration in accordance with another embodiment of thepresent invention.

FIG. 39 is a perspective view of the capture device illustrated in FIG.38 in an expanded configuration.

FIG. 40 is a side elevational view of a series of capture devices inaccordance with an embodiment of the present invention.

FIG. 41 is a side elevational view of a series of capture devices inaccordance with another embodiment of the present invention.

FIG. 42 is a side elevational view of a series of capture devices inaccordance with another embodiment of the present invention.

FIG. 43 is an enlarged perspective view of a distal portion of anobstruction removal system in accordance with an embodiment of thepresent invention.

FIG. 44 is a side sectional view of a distal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 45A is a side elevational view of a capture device in astraightened or unexpanded configuration in accordance with anembodiment of the present invention.

FIG. 45B is a side elevational view of the capture device illustrated inFIG. 45A in an expanded configuration.

FIG. 46 is a sectional view of an obstruction removal system inaccordance with another embodiment of the present invention.

FIG. 47 is a side elevational view of an obstruction removal system inaccordance with another embodiment of the present invention.

FIG. 48 is a side sectional view of the distal portion of theobstruction removal system illustrated in FIG. 47.

FIG. 49 is a side sectional view of a distal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 50 is a side sectional view of a distal portion of an obstructionremoval system in accordance with another embodiment of the presentinvention.

FIG. 51 is a perspective view of a distal portion of an obstructionremoval system having two drive belts in accordance with an embodimentof the present invention.

FIG. 52 is a cross-sectional view of the catheter shaft of theobstruction removal system of FIG. 51.

FIG. 53 is a side view of the distal portion of the obstruction removalsystem of FIG. 51 in accordance with an embodiment of the presentinvention.

FIG. 54 is a side view of the distal portion of the obstruction removalsystem of FIG. 51 in accordance with another embodiment of the presentinvention.

FIG. 55 is a perspective view of a distal portion of an obstructionremoval system having two drive belts in accordance with anotherembodiment of the present invention.

FIG. 56 is a cross-sectional view of the catheter shaft of theobstruction removal system of FIG. 55.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the present invention are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements. The terms “distal” and“proximal” are used in the following description with respect to aposition or direction relative to the treating clinician. “Distal” or“distally” are a position distant from or in a direction away from theclinician. “Proximal” and “proximally” are a position near or in adirection toward the clinician.

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Although the description of the invention is in the contextof treatment of blood vessels, arteries and veins, such as the cerebral,coronary, iliac, femoral, saphenous, carotid and renal, the inventionmay also be used in any other body passageways where it is deemeduseful. Furthermore, there is no intention to be bound by any expressedor implied theory presented in the preceding technical field,background, brief summary or the following detailed description.

Embodiments of the present invention are related to an obstructionremoval system for percutaneous removal of clots or obstructions withinthe vascular system using a plurality of capture or interference deviceson a band. The device may be used for treatment of acute stroke, byremoving the source of a vascular occlusion. In one embodiment, theobstruction removal system consists of three main components: amulti-lumen catheter, a plurality of circulating capture or interferencedevices, and a drive belt. The capture devices exit the catheter bodyvia a first lumen of the catheter, pass through the clot or obstructionwhile capturing small particles of the obstruction, and pull the clotparticles into a second lumen of the catheter. Rather than a singlecapture device that attempts to remove the entire clot or obstruction,the obstruction removal system of the present invention utilizes aplurality of capture or interference devices that each retrieve a smallportion of the clot or obstruction in order to remove the source ofvascular occlusion in a bit-by-bit or piecemeal fashion. The pluralityof capture or interference devices operate in a circulating orconveyor-like manner, meaning that the plurality of capture orinterference devices continuously move and advance through a circuitdefined by the lumens of the catheter. After a series of passes, theplurality of capture or interference devices collectively remove theentire source of the vascular occlusion.

The plurality of capture or interference devices may be, for example,basket or cage-like devices fixed to the drive belt. The capture devicesmay be cylindrical, spherical, bowl or umbrella shaped, elongated ovalshaped (i.e., watermelon-shaped), crescent or scoop shaped, spoolshaped, or any other appropriate configuration which may retrieve theobstruction material. The capture devices may be a mesh design or mayinclude strands that extend parallel to the drive belt. In anotherembodiment, the plurality of capture or interference devices may behairbrush-like or wire-brush devices having a plurality of bristles thatensnare portions of the clot or obstruction. The capture or interferencedevices may be fabricated out of a flexible material that allows them todeploy or expand upon exiting the first lumen of the catheter andcontract upon re-entry into the second lumen of the catheter. The numberof capture or interference devices, the geometry of such devices, thesize of such devices, and the spacing between adjacent devices may bevaried to optimize the clot or obstruction retrieval.

In one embodiment of the present invention, the drive belt may be awire. The plurality of capture devices may be formed by integral curly,protuberant or coiled sections of the wire. For example, the drive beltmay be a continuous wire coil, may include periodic coiled sections, ormay include a random protuberant or curly pattern. The drive belt andintegral capture devices may be fabricated out of a flexible,shape-memory material such as Nitinol. When formed from a shape memorymaterial, the wire drive belt may travel in a straightened configurationwithin the first lumen of the catheter during travel to the target site.Upon exiting a distal end of the catheter, the drive belt returns to itscoiled or curly configuration in order to form the capture devices andretrieve small particles of the obstruction. Upon re-entry into thecatheter via the second lumen, the drive belt remains in the coiled,protuberant, or curly configuration in order to retain the captured clotparticles.

In an embodiment, the obstruction removal system has a drive mechanismat its proximal end for driving the drive belt and capture devicesthrough the catheter. The drive mechanism may be a mechanicalpulley-like system manually, electronically, hydraulically,pneumatically, etc. operated by the device operator, which advances thedrive belt and capture devices located thereon through the catheter in acirculating or conveyor-like manner. “Circulating manner” as used hereinis intended to mean that the drive belt and capture devices locatedthereon move in a continuous manner through a cycle or circuit definedby the lumens of the catheter. In another embodiment, the drivemechanism may be an aspiration or vacuum source and/or a pressurizationsource at the proximal end of the obstruction removal system in order toadvance the drive belt and capture devices located thereon through thecatheter in a circulating or conveyor-like manner. In one embodiment,the pressurization source may include a fluid in order to providefurther breakdown of the clot or obstruction in addition to themechanical breakdown provided by the capture devices.

In an embodiment, the obstruction removal system includes means forremoving or cleaning the captured clot pieces from the capture devices.For example, in one embodiment of the present invention, the capturedclot is removed by a vacuum in communication with the proximal end ofthe obstruction removal system for pulling the captured clot particlesfrom the capture devices. The vacuum provides a suction force along thesecond lumen of the catheter, ensuring that loose clot particles do notmigrate downstream. In addition, the vacuum creates a negative pressureat the distal reentry port of the second lumen and thus may pull clotmaterial towards the capture devices, thus facilitating clot retrieval.In another embodiment, a fluid under pressure may be applied at theproximal end of the obstruction removal system in order to clean thecaptured clot particles from the drive belt and the capture devices asthey pass through the drive mechanism. In another example, the drivemechanism may include collinear pulleys in which the second pulleysqueegees or wipes the captured clot particles from the capture devicesas they pass through the intersection of the first and second pulleys.In yet another example, the drive mechanism is a single pulley and abrush-like element removes the captured clot particles from the capturedevices prior to reaching the single pulley.

In another embodiment of the present invention, a linear band having twoopposite ends is passed through the catheter via a dual-spoolconfiguration. The linear band may be a wire. One end of the band issecured to a first spool, and the other end of the band is secured to asecond spool. The band is wound around the first spool prior to usage,and the band is transferred to the second spool as it is advancedthrough the catheter. In this embodiment, the captured clot particleswould not have to be removed from the band and capture devices since theband operates in a non-circulating manner. “Non-circulating manner” asused herein is intended to mean that the band and capture deviceslocated thereon move through a path defined by the lumens of thecatheter but do not operate in a continuous manner through a cycle orcircuit. Further details and description of embodiments of the presentinvention are provided below with reference to FIGS. 1-56.

Obstruction Removal System

Referring to FIG. 1, obstruction removal system 100 is illustratedaccording to an embodiment of the present invention. Obstruction removalsystem 100 includes a catheter with an elongate multi-lumen shaft 102having a proximal end 104 and a distal end 106. A distal exit port 108and a distal reentry port 110 are located at the distal end 106 ofcatheter shaft 102. A drive belt 112 carries a plurality of capture orinterference devices 114 in a circulating or conveyor-like mannerthrough catheter shaft 102 via a drive mechanism 116 located at theproximal end 104 of catheter shaft 102. Drive belt 112 is an endlessloop having the plurality of capture or interference devices 114occurring along the length thereof that continuously moves and advancesthe capture devices 114 through a circuit or cycle defined by the lumensof catheter 102. Obstruction removal system 100 utilizes the pluralityof capture or interference devices 114 to remove a clot or obstructionin a bit-by-bit or piecemeal fashion. More particularly, following thedirectional arrows labeled on FIG. 1, drive belt 112 carrying capturedevices 114 exit catheter shaft 102 via distal exit port 108 of cathetershaft 102, pass through a clot or obstruction while retrieving smallparticles of the obstruction, and pull the captured clot particles backinto catheter shaft 102 via distal reentry port 110 of catheter shaft102. After a series of passes or cycles, the plurality of capture orinterference devices 114 collectively remove the entire source of thevascular occlusion.

FIG. 2A is a cross-sectional view of obstruction removal system 100taken along line A-A of FIG. 1 in accordance with an embodiment of thepresent invention. Catheter shaft 102 has an outside surface 218 anddefines dual side-by-side lumens extending there through. First lumen220A is formed via an inside surface 222A and extends the length ofcatheter shaft 102 from the proximal end 104 to the distal end 106,terminating in distal exit port 108. Second lumen 224A is formed via aninside surface 226A and extends the length of catheter shaft 102 fromthe proximal end 104 to the distal end 106, terminating in distalreentry port 110. As shown in FIG. 2A, side-by-side first lumen 220A andsecond lumen 224A may each have a circular cross-section and be of anapproximately equal size or diameter. The size or diameter of firstlumen 220A and second lumen 224A must each be sufficient to receive theplurality of capture devices 114. In addition, it will be apparent tothose of ordinary skill in the art that first lumen 220A and secondlumen 224A may have any appropriate cross-sectional shape. For example,as shown in FIG. 2B, first lumen 220B and second lumen 224B mayalternatively each have a semi-circular cross-section.

FIG. 3 is a sectional view of the distal end 106 of catheter shaft 102placed within a blood vessel 330 such that obstruction removal system100 may be utilized to remove clot or obstruction 328. Drive belt 112having a plurality of capture or interference devices 114 thereonextends through first lumen 220 and second lumen 224 of catheter shaft102. Drive mechanism 116 operates to circulate the plurality of capturedevices 114 through catheter shaft 102 in a conveyor-like manner. Morespecifically, following the directional arrows labeled on FIG. 3, drivemechanism 116 operates to essentially pull the plurality of capturedevices 114 through second lumen 224 such that they exit catheter shaft102 via distal exit port 108. The plurality of capture devices 114 thenpass through clot or obstruction 328 while capturing small particlesthereof. Capture devices 114 re-enter catheter shaft 102 via distalreentry port 110 and carry or direct the captured clot particles throughsecond lumen 224 of the catheter shaft 102 to be cleansed or removedthere from.

Thus, obstruction 328 within a body lumen is removed by positioningobstruction removal system 100 near the obstruction within the bodylumen and circulating drive belt 112 though catheter shaft 102 such thatthe plurality of capture devices 114 are advanced through the firstlumen 220, through the distal exit port 108, through the distal reentryport 110 and through the second lumen 224. At least a portion ofobstruction 328 is removed from the body lumen in a bit-by-bit fashionas each capture device 114 travels between distal exit port 108 anddistal reentry port 110 of catheter shaft 102. The entire obstruction328 is removed from the body lumen after drive belt 112 and theplurality of capture devices 114 located thereon are circulated throughcatheter shaft 102 in a series of passes.

Catheter Shaft

FIGS. 21A-24B illustrate alternative embodiments for catheter shaft 102,which guide or track drive belt 112 with capture devices 114. Oneembodiment illustrated in FIGS. 21A-21B contains a track 2180 created byan extension 2181 of distal end 2106 of catheter shaft 2102. Extension2181 is a band of material that distally extends from distal end 2106 ofcatheter shaft 2102 and spans the entire diameter of catheter shaft2102. Track 2180 is a semi-circular groove formed on opposing sides ofextension 2181 that is coaxially aligned with the first lumen (notshown) and the second lumen (not shown) in order to guide capturedevices 114 between distal exit port 2108 and distal reentry port 2110of catheter shaft 2102. Extension 2181 and track 2180 may be formed byremoving a portion of catheter shaft 2102, or may be formed as aseparate piece and attached to the distal end 2106 of catheter shaft2102.

Another embodiment illustrated in FIGS. 22A-22B contains a track 2280created by extension 2281 of distal end 2206 of catheter shaft 2202.Track 2280 is similar to track 2180 in that extension 2281 is a band ofmaterial that distally extends from distal end 2206 of catheter shaft2202. However, extension 2281 does not span the entire diameter ofcatheter shaft 2202 and includes tapered outer surfaces rather thansemi-circular outer surfaces as in the embodiment of FIGS. 21A-21B.Track 2280 is a semi-circular groove formed on opposing sides ofextension 2281 that is coaxially aligned with the first lumen (notshown) and the second lumen (not shown) in order to guide capturedevices 114 between distal exit port 2208 and distal reentry port 2210of catheter shaft 2202. Extension 2281 and track 2280 may be formed byremoving a portion of catheter shaft 2202, or may be formed as aseparate piece and attached to the distal end 2206 of catheter shaft2202.

Another embodiment for guiding or tracking drive belt 112 with capturedevices 114 thereon over distal end 106 of catheter shaft 102 isillustrated in FIGS. 23A-23B. This embodiment includes a notch or ridge2382 that is cut out of distal end 2306 of catheter shaft 2302 and spansthe entire diameter of catheter shaft 2302. Notch 2382 has a depthapproximately equal to half the outer diameter of a capture device 114so that half of each capture device 114 will extend beyond distal end2306 of catheter shaft 2302 in order to retrieve the target clotmaterial. Capture devices 114 ride along notch 2382 which thus helps toguide capture devices 114 between distal exit port 2308 and distalreentry port 2310 of catheter shaft 102. When notch 2382 spans theentire diameter of catheter shaft 2302, the entire capture device 114 isexposed from the catheter shaft, as shown in FIG. 23B. Notch 2382 may beformed by removing a portion of catheter shaft 2302.

Another embodiment illustrated in FIGS. 24A-24B contains a notch orridge 2482 that is cut out of distal end 2406 of catheter shaft 2402.Notch 2482 is similar to notch 2382 except that notch 2482 does not spanthe entire diameter of catheter shaft 2402. Since notch 2482 does notspan the entire diameter of catheter shaft 2402, only a portion ofcapture device 114 is exposed from the catheter shaft, as shown in FIG.24B. Notch 2482 has a depth approximately equal to half the outerdiameter of a capture device 114 so that half of each capture device 114will extend beyond distal end 2406 of catheter shaft 2402 in order toretrieve the target clot material. Capture devices 114 ride along notch2482 which thus helps to guide capture devices 114 between distal exitport 2408 and distal reentry port 2410 of catheter shaft 2402. Notch2482 may be formed by removing a portion of catheter shaft 2402.

Catheter shaft 102 may be an extruded multi-lumen shaft formed of anysuitable flexible polymeric material. Non-exhaustive examples ofmaterial for catheter shaft 102 are polyethylene terephalate (PET),nylon, polyethylene, PEBAX, or combinations of any of these, eitherblended or co-extruded. Optionally, a portion of catheter shaft 102 maybe formed as a composite having a reinforcement material incorporatedwithin a polymeric body in order to enhance strength, flexibility,and/or toughness. Suitable reinforcement layers include braiding, wiremesh layers, embedded axial wires, embedded helical or circumferentialwires, and the like. In an embodiment, proximal end 104 of cathetershaft 102 may in some instances be formed from a reinforced polymerictube, for example, as shown and described in U.S. Pat. No. 5,827,242 toFollmer et al. which is incorporated by reference herein in itsentirety.

Catheter shaft 102 may include a separate guidewire lumen in order totrack obstruction removal system 100 to the target obstruction. Forexample, in one embodiment illustrated in FIGS. 25A-25B, catheter shaft2502 includes a guidewire lumen 2586 for receiving a guidewire (notshown). In such an embodiment, obstruction removal system 2500 includesthree lumens extruded within catheter shaft 2502: the first lumen (notshown) and the second lumen (not shown) for tracking capture devices 114and drive belt 112 through catheter shaft 102, and guidewire lumen 2586.In FIGS. 25A-25B, catheter 2502 has a substantially circularcross-section with a semi-circular protrusion extending therefrom inwhich guidewire lumen 2586 is at least partial situated. Guidewire lumen2586 may extend the entire length of catheter shaft 2502 in anover-the-wire configuration. However, as would be understood by one ofordinary skill in the art, guidewire lumen 2586 may alternately extendonly within the distal portion of catheter shaft 2502 in arapid-exchange configuration. Guidewire lumen 2586 is off-center tocatheter shaft 2502 in order to reduce the incidence of capture devices114 and/or drive belt 112 from coming into contact with the guidewire.During operation, the guidewire may be pulled proximally withinguidewire lumen 2586 in order to further prevent interruption with theclot retrieving function of obstruction removal system 2500. FIGS.25A-25B illustrate catheter shaft 2502 including an extension 2181 ofdistal end 2506 of catheter shaft 2502, which forms a track for guidingthe capture devices and drive belt similar to that described above withrespect to FIGS. 21A-21B.

Another embodiment of an obstruction removal system with a guidewirelumen is illustrated in FIGS. 26A-26B. Catheter shaft 2602 includes aguidewire lumen 2686 for receiving a guidewire (not shown). In such anembodiment, obstruction removal system 2600 includes three lumensextruded within catheter shaft 2602: the first lumen (not shown) and thesecond lumen (not shown) for tracking capture devices 114 and drive belt112 through catheter shaft 102, and guidewire lumen 2686. In FIGS.26A-26B, catheter shaft 2602 has a substantially triangularcross-section to accommodate the three lumens. The triangularcross-section minimizes the crossing profile of the catheter shaft 2602.Guidewire lumen 2686 may extend the entire length of catheter shaft 2602in an over-the-wire configuration or may alternately extend only withinthe distal portion of catheter 2602 in a rapid-exchange configuration.Guidewire lumen 2686 is off-center to catheter shaft 2602 in order toreduce the incidence of capture devices 114 and/or drive belt 112 fromcoming into contact with the guidewire. During operation, the guidewiremay be pulled proximally within guidewire lumen 2686 in order to furtherprevent interruption with the clot retrieving function of obstructionremoval system 2600. FIGS. 26A-26B illustrate catheter shaft 2602including an extension of distal end 2606 of catheter shaft 2602, whichforms a track for guiding the capture devices and drive belt similar tothat described above with respect to FIGS. 21A-21B.

Another embodiment of an obstruction removal system having a guidewirelumen is illustrated in FIGS. 27A-27B. Catheter shaft 2702 includes aguidewire lumen 2786 for receiving a guidewire (not shown). Guidewirelumen 2786 has a distal portion defined by a guidewire lumen extension2784 that extends beyond the distal exit and reentry ports of cathetershaft 2702 in order to reduce the incidence of capture devices 114and/or drive belt 112 from coming into contact with the guidewire.Obstruction removal system 2700 includes three lumens extruded withincatheter shaft 2702: the first lumen (not shown) and the second lumen(not shown) for tracking capture devices 114 and drive belt 112 throughcatheter shaft 102, and guidewire lumen 2786. Guidewire lumen 2786 mayextend the entire length of catheter shaft 2702 in an over-the-wireconfiguration or may alternately extend only within the distal portionof catheter shaft 2702 in a rapid-exchange configuration. In FIGS.27A-27B, catheter shaft 2702 has a substantially triangularcross-section to accommodate the three lumens. This triangularcross-section minimizes the crossing profile of the catheter shaft 2702.Guidewire lumen 2786 is off-center to catheter shaft 2702 in order tofurther reduce the incidence of capture devices 114 and/or drive belt112 from coming into contact with the guidewire. During operation, thedistal end 2706 of catheter shaft 2702, which is on guidewire lumenextension 2784, is preferably embedded within the clot. The capturedevices 114 exiting from the distal exit port of the catheter shaft 2702would thus be allowed to come into contact with the proximal end of theclot.

Another embodiment of an obstruction removal system having a guidewirelumen is illustrated in FIGS. 28A-28C. Catheter shaft 2802 includes atubular guidewire shaft 2884 that defines guidewire lumen 2886 forreceiving a guidewire (not shown). Guidewire shaft 2884 is attached tothe outside surface of catheter shaft 2802. In such an embodiment,obstruction removal system 2800 includes three lumens: the first lumen(not shown) and the second lumen (not shown) for tracking capturedevices 114 and drive belt 112 through catheter shaft 102, and guidewirelumen 2886. The first lumen and the second lumen are both extrudedwithin catheter shaft 2802, while guidewire lumen 2886 is attached tothe outside surface of catheter shaft 2802. In FIGS. 28A-28C, cathetershaft 2802 has a substantially oval or oblong cross-section toaccommodate the three lumens. This oval or oblong cross-sectionminimizes the crossing profile of the catheter shaft 2802. As shown inFIGS. 28A-28C, guidewire shaft 2884 may be a cylindrical hypotubeextending along only the distal portion of catheter shaft 2802 in arapid-exchange configuration. However, as would be understood by one ofordinary skill in the art, guidewire shaft 2884 and guidewire lumen 2886formed thereby may alternately extend the entire length of cathetershaft 2802 in an over-the-wire configuration. During operation, theguidewire may be pulled proximally within guidewire lumen 2886 in orderto prevent interruption with the clot retrieving function of obstructionremoval system 2800.

Capture Devices

The plurality of capture devices may assume various forms. FIG. 4 is anenlarged perspective view of distal end 106 of catheter shaft 102showing capture devices 114 circulating within catheter shaft 102through a path defined by first lumen 220 and second lumen 224. As shownin FIGS. 4-5, capture devices 114 may be a spherical basket 532 fixed todrive belt 112. The outer diameter of spherical basket 532 isapproximately 0.010 inches to 0.020 inches. The relatively smaller sizeof capture devices 114 minimizes the size of obstruction removal system100 such that obstruction removal system 100 may fit within relativelysmall vessels, and at the same time, collectively retrieve relativelylarge emboli. Baskets 532 may include strands 534 that extend parallelto drive belt 112 and parallel to blood flow when located within thebody lumen.

In another embodiment illustrated in FIG. 6, capture devices 614 may bea bowl or umbrella shaped basket 638 fixed to drive belt 112. Baskets638 may have an outer diameter similar to that of spherical basket 532of FIG. 5 or may expand to a greater diameter. Baskets 638 may includestrands 634 that extend parallel to drive belt 112 and parallel to bloodflow when located within the body lumen.

In another embodiment illustrated in FIG. 7, capture devices 714 may bean elongated oval (i.e., watermelon-shaped) basket 740 fixed to drivebelt 112. Baskets 740 may have an outer diameter similar to that ofspherical basket 532 of FIG. 5 or may have a greater or lesser diameter.Baskets 740 may include strands 734 that extend parallel to drive belt112 and parallel to blood flow when located within the body lumen.

In another embodiment illustrated in FIG. 8, capture devices 814 may bea spherical basket 832 fixed to drive belt 112. Baskets 832 may have anouter diameter similar to that of spherical basket 532 of FIG. 5.Baskets 832 are formed of a woven or stamped mesh 836 to captureparticles of a clot or obstruction.

In another embodiment illustrated in FIG. 9, capture devices 914 may bea bowl or umbrella shaped basket 938 fixed to drive belt 112. Baskets938 may expand to an outer diameter similar to or greater than that ofspherical basket 832 of FIG. 8. Baskets 938 are also formed of a wovenor stamped mesh 936 to capture particles of a clot or obstruction.

In another embodiment illustrated in FIG. 10, capture devices 1014 maybe an elongated oval (i.e., watermelon-shaped) basket 1040 fixed todrive belt 112. Baskets 1040 may have an outer diameter similar to, orgreater or lesser than that of spherical basket 832 of FIG. 8. Baskets1040 are formed of a woven or stamped mesh 1036 to capture particles ofa clot or obstruction.

In another embodiment illustrated in FIG. 31, capture devices 3114 maybe a crescent or scoop shaped basket 3111 fixed to drive belt 112.Baskets 3111 may have an outer diameter similar to that of sphericalbasket 532 of FIG. 5 or may expand to a greater diameter. Baskets 3111may be fabricated from a solid piece of material, and/or may includestrands or a woven or stamped mesh to capture particles of a clot orobstruction.

In another embodiment illustrated in FIG. 33, capture devices 3314 maybe a spool shaped basket 3317 fixed to drive belt 112. Each spool shapedbasket 3317 has flared end portions such that the diameter at the centerof basket 3317 is smaller than the diameter at the ends of basket 3317.Baskets 3317 may have an outermost diameter similar to that of sphericalbasket 532 of FIG. 5 or may expand to a greater diameter. Baskets 3317are formed of a woven or stamped mesh 3336 to capture particles of aclot or obstruction, or may include strands that extend parallel todrive belt 112 and parallel to blood flow when located within the bodylumen.

In another embodiment illustrated in FIG. 34, capture devices 3414 maybe a spherical basket 3419 fixed to drive belt 112. Baskets 3419 includea closed basket portion 3423 on one half of the spherical structure, andan open filter portion 3421 on the other half of the sphericalstructure. Baskets 3419 may have an outermost diameter similar to thatof spherical basket 532 of FIG. 5 or may expand to a greater diameter.Open filter portion 3421 includes strands 3434 that extend parallel todrive belt 112 and parallel to blood flow when located within the bodylumen. Closed basket portion 3423 may be fabricated from a solid pieceof material, or may include a woven or stamped mesh to capture particlesof a clot or obstruction.

Various embodiments of expandable capture devices according to thepresent invention are illustrated in FIGS. 38-45B. Illustrated in FIGS.38-39, capture device 3814 is a tubular segment having parallel slits3839 that extend longitudinally and are spaced around a circumferencethereof. Slits 3839 have a length less than the length of the tubularsegment so that when opposing ends of the tubular segment are drawntoward one and other, the tubular segment is compressed such thatcapture device 3814 radially expands with the strands of materialbetween slits 3839 forming a spherical basket. Capture device 3814 isprocessed or manufactured so as to remain in the expanded state of FIG.39. Longitudinal slits 3839 may be laser cut into the tubular segment.The outer diameter of the spherical basket formed by slits 3839 isapproximately 0.010 inches to 0.020 inches.

In one embodiment, the tubular segment for forming capture device 3814may be the drive belt. For example, shown in FIG. 40, capture devices3814 are formed integrally with drive belt 4012, and made to remain inan expanded state allowing a series of slits 3839 to form a series ofspherical baskets therein. Drive belt 4012 may also include a coiled cut4041 in the straight portion of drive belt 4012 for additionalflexibility.

In another embodiment, the tubular segment forms a single capture device3814 that is attached to the drive belt in an expanded form. Forexample, as shown in FIG. 41, capture devices 3814 are formed from atubular segment 4143 when slits 3839 are expanded to form a sphericalbasket. Tubular segment 4143 is a hollow tube having an inner diameterthat is slightly greater than the outer diameter of drive belt 112 sothat tubular segment 4143 may be slid over and attached to drive belt112. Tubular segment 4143 contains one set of longitudinal slits 3839formed therein. In order to form a plurality of capture devices on drivebelt 112, a plurality of spaced apart tubular segments 4143 arepositioned in an expanded configuration over drive belt 112.

In yet another embodiment, the tubular segment forms a series of capturedevices 3814 and is a separate, continuous tube that is mounted overand/or attached to the drive belt 112. For example, as shown in FIG. 42,a series of capture devices 3814 are formed on a tubular segment 4243.Tubular segment 4243 is slightly longer than drive belt 112 so that whentubular segment 4243 is slid over drive belt 112, compressed andattached to drive belt 112, slits 3839 are compressed and expanded toform spherical baskets. Tubular segment 4243 is a hollow tube having aninner diameter that is slightly greater than the outer diameter of drivebelt 112 so that tubular segment 4243 may be slid over and attached todrive belt 112. Tubular segment 4243 contains a plurality oflongitudinally spaced sets of slits 3839 formed therein in order to forma plurality of capture devices on drive belt 112.

When either drive belt 4012 or tubular segment 4243 forms capturedevices 3814, capture devices 3814 may expand once they exit cathetershaft 102 via distal exit port 108. In one such embodiment illustratedin FIG. 43, catheter shaft 102 surrounds and contains capture devices3814 in a radially contracted or compressed configuration when thecapture devices are located within first lumen 220 of catheter shaft 102and within second lumen 224 of catheter shaft 102. Traveling in aradially contracted or compressed configuration minimizes the sizerequired for first lumen 220 and second lumen 224, thus minimizing thesize of obstruction removal system 100 such that obstruction removalsystem 100 may fit within relatively small vessels. However, the exposedcapture devices 3814 are not contracted by the inner diameters of thecatheter lumens between distal exit port 108 and distal reentry port110. The exposed capture devices 3814 radially expand between distalexit port 108 and distal reentry port 110 so that the strands ofmaterial between slits 3839 form a spherical basket.

In another such embodiment illustrated in FIG. 44, catheter shaft 102surrounds and contains capture devices 3814 in a radially contracted orcompressed configuration when the capture devices are located withinfirst lumen 220 of catheter shaft 102 but capture devices 3814 remain inthe expanded configuration when traveling through second lumen 224 ofcatheter shaft 102. Thus, the size required for first lumen 220 isminimal and thus the overall size of catheter shaft 102 may be reducedand/or the size for a second lumen 224 may be maximized. The exposedcapture devices 3814 are not contracted by the inner diameter of firstlumen 220 once they exit distal exit port 108. The exposed capturedevices 3814 radially expand once they exit distal exit port 108 so thatthe strands of material between slits 3839 form a spherical basket. Uponre-entry into catheter 102 via a distal reentry port 110, second lumen224 is of such a size to allow capture devices 3814 to remain in theirexpanded configuration as they travel through second lumen 224 so thatthe captured clot particles 4428 are retained in capture devices 3814.

When tubular segment 4143 forms capture device 3814, capture devices3814 may be loosely fixed on drive belt 112 between two stoppers so thatcapture device 3814 expands once it encounters a portion of clot orobstruction. Illustrated in FIG. 45A, tubular segment 4143 having oneset of slits 3839 formed therein is slid over drive belt 112 and locatedbetween two annular stops 4545. The annular stops 4545 are separatedfrom each other a sufficient distance to allow tubular segment 4143 totravel through catheter shaft 102 in a straightened configuration.Traveling in a straightened configuration minimizes the size requiredfor first lumen 220 of catheter shaft 102 as described above withrespect to FIG. 44. However, shown in FIG. 45B, compression andsubsequent expansion of tubular segment 4143 occurs when segmentedtubular segment 4143 encounters a portion of clot or obstruction 4528.The clot material causes capture devices 3814 to radially expand so thatthe strands of material between slits 3839 form a spherical basket. Uponre-entry into catheter 102 via a distal reentry port 110, capture device3814 remains in a semi-expanded configuration with the clot particle4528 captured within the slits 3839 as it travels through second lumen224 so that the captured clot particles are retained in capture device3814.

FIGS. 5-10, 31, 33-34, and 38-39 illustrate that the capture devices maybe basket or cage-like devices fixed to drive belt 112. The shape of thecapture devices may be, for example, cylindrical, spherical, bowl orumbrella shaped, elongated oval shaped (i.e., watermelon-shaped),crescent or scoop shaped, or spool shaped. In each of these embodiments,it will be apparent to those of ordinary skill in the art that portionsor particles of a clot or obstruction may be ensnared or caught withinthe inner area of the capture devices (that is, the captured clotparticles are contained within the capture devices). However, it will beapparent to those of ordinary skill in the art that the capture devicesmay have any suitable configuration that will retrieve the obstructionmaterial in a bit-by-bit or piecemeal fashion.

Alternatively or in addition, the capture devices may operate as aninterference device that detaches or separates portions or particles ofa clot or obstruction and then operates to push or pull these detachedclot portions or particles into the second lumen of the catheter (thatis, the captured clot particles are advanced by the capture devices).For example, in another embodiment of the present invention illustratedin FIG. 11, capture devices 1114 may be a hairbrush-like interferencedevice 1133 fixed to drive belt 112. Hairbrush-like interference device1133 has an outer diameter that may be similar to that of sphericalbasket 532 of FIG. 5. Hairbrush-like interference device 1133 includesbristles 1135 that radially extend from drive belt 112 to ensnare orcatch a portion of a clot or obstruction. Bristles 1135 may be formed ofany suitable material, including but not limited to PEBAX, nylon,polyimide, PEEK, polyethylene terephalate (PET) polyurethane,polyethylene, polypropolyne, stainless steel, nickel titanium, MP35N,and tantalum. As drive belt 112 and hairbrush-like interference device1133 located thereon pass over a target clot, clot particles areensnared or caught in bristles 1135. Spaced apart engaging protrusions1137 may be present between hairbrush-like interference devices 1133 forengaging a pulley of the driving mechanism in order to pull drive belt112 at a constant speed and for providing room for larger trapped clotparticles that may be attached to the drive belt 112. Although shown inconjunction with hairbrush-like interference devices 1133, protrusions1137 may be utilized between any type of capture devices. Protrusions1137 will be further explained with reference to FIG. 30 below.

In another embodiment of the present invention illustrated in FIG. 32,capture devices 3214 may be a wire-brush interference device 3215 fixedto drive belt 112. Wire-brush interference device 3215 has an outerdiameter that may be similar to that of spherical basket 532 of FIG. 5.Wire-brush interference device 3215 includes a plurality of curlystrands that extend from drive belt 112 to ensnare or catch a portion ofa clot or obstruction. The strands may be formed of any suitablematerial, including but not limited to stainless steel, nickel titanium,MP35N, tantalum, PEBAX, nylon, polyimide, PEEK, polyethylene terephalate(PET) polyurethane, polyethylene, and polypropylene. As drive belt 112and wire-brush interference device 3215 located thereon pass over atarget clot, clot particles are ensnared or caught in the strands.

In another embodiment of the present invention illustrated in FIG. 35,capture devices 3514 may be a bead-like interference device 3525 fixedto drive belt 112. Bead-like interference device 3525 is a solidpolymeric sphere attached to or integral with drive belt 112. Thepolymeric sphere may be formed of any suitable material, including butnot limited to PEBAX, nylon, polyimide, PEEK, polyethylene terephalate(PET) polyurethane, polyethylene, and polypropolyne. Bead-likeinterference device 3525 has an outer diameter that may be similar tothat of spherical basket 532 of FIG. 5 or may have a greater or lesserdiameter. The plurality of bead-like interference devices 3525 detach orseparate portions or particles of a clot or obstruction and then operateto push or pull these detached clot portions or particles into thesecond lumen of the catheter. In other words, the captured clotparticles are advanced by bead-like interference devices 3525.

In another embodiment of the present invention illustrated in FIG. 36,capture devices 3614 may be a balloon interference device 3629 fixed todrive belt 112. Balloon interference device 3629 is a polymeric balloonattached to or integral with drive belt 112. The polymeric balloon maybe formed of any suitable material, including but not limited to PEBAX,nylon, polyethylene terephalate (PET) polyurethane, polyethylene, andpolypropolyne. Balloon interference device 3629 has an outer diameterthat may be similar to that of spherical basket 532 of FIG. 5 or mayhave a greater or lesser diameter. The plurality of balloon interferencedevices 3629 detach or separate portions or particles of a clot orobstruction and then operate to push or pull these detached clotportions or particles into the second lumen of the catheter. In otherwords, the captured clot particles are advanced by balloon interferencedevices 3629.

In another embodiment of the present invention illustrated in FIG. 37,capture devices 3714 may be a burr-like interference device 3731 fixedto drive belt 112. Burr-like interference device 3731 is a solidpolymeric portion having a jagged, raised and/or an abrasive outersurface for improved cutting into a portion of a clot or obstruction.The polymeric burr may be formed of any suitable material, including butnot limited to PEBAX, nylon, polyethylene terephalate (PET)polyurethane, polyethylene, and polypropolyne. Burr-like interferencedevice 3731 has an outer diameter that may be similar to that ofspherical basket 532 of FIG. 5 or smaller than that of spherical basket532 or may have a greater or lesser diameter.

The capture devices illustrated in FIGS. 5-11, 31-34, and 38-42 abovemay be fabricated from a flexible material that allows the capturedevices to deploy or expand upon exiting first lumen 220 of cathetershaft 102 and contract or compress upon re-entry into second lumen 224of catheter shaft 102. For example, the capture devices may beconstructed out of a spring-type or superelastic material such asnickel-titanium (nitinol), a nickel-tin alloy, a shape memory material,and other superelastic materials. In such an embodiment, catheter shaft102 surrounds and contains at least portion of the capture devices in acontracted or compressed configuration when the capture devices arelocated within first lumen 220 of catheter shaft 102. Once the capturedevices exit catheter shaft 102 via distal exit port 108, the capturedevices are released to assume their expanded or deployed configuration.Upon re-entry into catheter shaft 102 via distal reentry port 110, thecapture devices resume a contracted or compressed position in order toadvance through second lumen 224 of catheter shaft 102. Constructing thecapture devices out of a compressible material minimizes the sizerequired for first lumen 220 and second lumen 224, thus minimizing thesize of obstruction removal system 100 such that obstruction removalsystem 100 may fit within relatively small vessels. However, the capturedevices may also be formed from a more rigid material. For example,suitable metallic materials include stainless steel, nickel-cobalt alloysuch as MP35N, and cobalt-chromium. For increased radiopacity, thecapture devices may be formed from or to include tantalum, titanium,platinum, gold, silver, palladium, iridium, and the like. In anotherembodiment, a wire formed from tantalum, titanium, platinum, gold,silver, palladium, iridium, and the like may be wrapped or coiled aboutdrive belt 112 and/or the capture devices to increase the radiopacitythereof.

In another embodiment of the present invention, drive belt 112 and theplurality of capture devices 114 may be an integral or one-piececonveyor or circulating element having integral curly, protuberant, orcoiled sections formed by a wire element that also comprises the drivebelt. For example, as shown in FIG. 12, conveyor or circulating element1213 is a wire element having a plurality of “capture devices” formed byintegral coiled sections 1242 thereof that are separated by straightsections 1244. In another embodiment shown in FIG. 13, the conveyor orcirculating element 1313 is a continuous wire coil element. In anotherembodiment shown in FIG. 14, conveyor or circulating element 1413 is awire element having a plurality of “capture devices” formed by integralcoiled sections 1442 thereof with straight sections 1444 there between.Coiled sections 1442 have tapered ends 1446 on both sides thereof. Inyet another embodiment shown in FIG. 15, conveyor or circulating element1513 is a wire element having a plurality of “capture devices” formed byintegral random protuberant sections 1548 thereof. It will be apparentto those of ordinary skill in the art that when the conveyor orcirculating element is a wire, it may be formed into variousconfigurations to form capture devices in addition to those embodimentsillustrated in FIGS. 12-15.

The integral conveyor or circulating elements illustrated in FIGS. 12-15may be constructed out of any appropriate material. For example,suitable metallic materials include stainless steel, nickel-cobalt alloysuch as MP35N, and cobalt-chromium. For increased radiopacity, theintegral conveyor or circulating elements may be constructed from or toinclude tantalum, titanium, platinum, gold, silver, palladium, iridium,and the like. In another embodiment, a wire formed from tantalum,titanium, platinum, gold, silver, palladium, iridium, and the like maybe wrapped or coiled about the integral conveyor or circulating elementsto increase the radiopacity thereof.

In another embodiment, the integral conveyor or circulating elements maybe constructed out of a spring-type or superelastic material such asnickel-titanium (nitinol), a nickel-tin alloy, a shape memory material,and other superelastic materials. Deployment of the capture devices maybe effected by utilizing the superelastic or shape memorycharacteristics of a material. More particularly, the integral conveyoror circulating elements may have two states of size or shape, astraightened configuration sufficient for delivery to the treatment siteand a deployed or expanded configuration forming the capture devices inorder to capture or retrieve a portion of a clot or obstruction at thetreatment site. In one embodiment, the deployed or expandedconfiguration of the integral conveyor or circulating elements may beachieved by utilizing elastic or superelastic characteristics of amaterial. The integral conveyor or circulating elements may bemechanically deformed into the straightened configuration when locatedwithin the first lumen of the catheter. Once the integral conveyor orcirculating elements exit the catheter via the distal exit port, theintegral conveyor or circulating elements elastically retain their shapeand thus assume their expanded or deployed configuration. In anotherembodiment, the deployed or expanded configuration of the integralconveyor or circulating elements may be achieved by utilizingtemperature-dependent characteristics of a material. More particularly,some shape memory metals have the ability to return to a defined shapeor size when subjected to certain thermal or stress conditions. Shapememory metals are generally capable of being deformed at a relativelylow temperature and, upon exposure to a relatively higher temperature,return to the defined shape or size they held prior to the deformation.The integral conveyor or circulating elements may be deformed into thestraightened configuration when located within the first lumen of thecatheter. Once the integral conveyor or circulating elements exit thecatheter via the distal exit port, the integral conveyor or circulatingelements may assume their “remembered” deployed or expandedconfiguration once exposed to a higher temperature, i.e., bodytemperature, in vivo.

The advantages of utilizing a superelastic or shape memory material forthe integral conveyor or circulating elements are illustrated in FIGS.16-16A. FIG. 16 is a sectional view of a obstruction removal system 1600in accordance with another embodiment of the present invention, whileFIG. 16A is a cross-sectional view taken along line A-A of FIG. 16.Similar to the embodiment depicted in FIG. 15, integral conveyor orcirculating element 1513 is a wire element with a plurality of capturedevices comprised of integral random protuberant sections 1548 formedtherein. Integral conveyor or circulating element 1513 is formed of amaterial having superelastic or shape memory characteristics asdescribed above. The superelastic or shape memory characteristics enableconveyor or circulating element 1513 to travel in a deformed,straightened state within a first lumen 1620 of catheter 1602. Thus, thesize required for first lumen 1620 is minimal and thus the overall sizeof catheter 1602 may be reduced and/or the size for a second lumen 1624may be maximized. When conveyor or circulating element 1513 exits adistal portion 1606 of catheter 1602 via a distal exit port 1608,protuberant capture devices 1548 may assume their “remembered” deployedor expanded configuration. Upon re-entry into catheter 1602 via a distalreentry port 1610, conveyor or circulating element 1513 remains in itsprotuberant configuration as it travels through second lumen 1624 sothat the captured clot particles are retained in capture devices 1548.In order to ensure that loose clot particles do not migrate downstream,the second lumen 1624 may contain a negative pressure or vacuum forpulling the captured clot particles proximally as described herein withrespect to FIG. 46 and/or FIG. 30. The negative pressure or vacuum keepssecond lumen 1624 free from clot particles that may dislodge during thecirculation of conveyor or circulating element 1513 through second lumen1624, thus keeping second lumen 1624 clear of debris or self-cleaning.Further, the negative pressure at the distal reentry port 1610 of secondlumen 1624 may pull the clot towards conveyor or circulating element1513 thus facilitating the retrieval of a small portion of the clot orobstruction in order to remove the source of vascular occlusion in abit-by-bit or piecemeal fashion. At a proximal end 1604 of catheter1602, catheter 1602 includes a transition section 1627 for transitioningconveyor or circulating element 1513 from second lumen 1624 into a drivemechanism 1616. Transition section 1627 has a tapered shape in order tofunnel conveyor or circulating element 1513 from second lumen 1624 intodrive mechanism 1616. Although FIGS. 16-16A have been describedutilizing conveyor or circulating element 1513 with integral randomprotuberant or curly sections 1548 formed therein, it will be apparentto those skilled in the art that the conveyor or circulating element mayhave other deployed or expanded configurations such as those describedabove with respect to FIGS. 12-14. For example, the conveyor orcirculating element may assume a “remembered” continuous or periodiccoiled shape once it exits catheter 1602 via distal exit port 1608.

As shown above, the plurality of capture devices may assume variousforms. For example, the plurality of capture or interference devices maybe basket or cage-like devices fixed to the drive belt that operate tocatch portions or particles of a clot or obstruction within the innerarea of the capture devices (that is, contained within the capturedevices). In other embodiments, the plurality of capture devices mayoperate as interference devices that detach or separate portions orparticles of a clot or obstruction and then operate to push or pullthese detached clot portions or particles into the second lumen of thecatheter (that is, the captured clot particles are advanced by thecapture devices). In yet another embodiment, the plurality of capturedevices may be formed by integral curly, protuberant, or coiled sectionsof a conveyor or circulating element that operate to contain and/oradvance portions or particles of a clot or obstruction. “Captured” clotor obstruction particles as used herein is intended to refer to bothscenarios, i.e., particles contained within the capture devices andparticles advanced by the capture devices.

As previously stated, the geometry and size of the capture orinterference devices may be varied to optimize the clot or obstructionretrieval. In addition, the number of such devices and the spacingbetween adjacent devices may also be varied to optimize the clot orobstruction retrieval. For example, the spacing between adjacent capturedevices may be regular or evenly-spaced along the length of the drivebelt or may be irregular or unevenly-spaced along the length of thedrive belt. In addition, the plurality of capture devices may extendalong the entire length of the drive belt, or may extend along onlyportion of the drive belt.

Drive Mechanisms

Embodiments of the obstruction removal system of the present inventionmay include one or more drive mechanisms on its proximal end for drivingthe drive belt and capture devices located thereon through themulti-lumen catheter. A drive mechanism operates to essentially pull theplurality of capture devices through the first lumen of the cathetersuch that they exit the catheter via a distal exit port and pull theplurality of capture devices, having captured clot particles therein,through a second lumen of the catheter via distal reentry port. Theplurality of capture devices operate in a circulating or conveyor-likemanner, meaning that the drive mechanism continuously moves and advancesthe capture devices through a circuit defined by the lumens of thecatheter. After a series of passes, the plurality of capture devicescollectively removes the entire source of the vascular occlusion.

In one embodiment, the drive mechanism may be a mechanical pulley systemmanually operated by the device operator which advances drive belt 112and the capture devices located thereon through catheter shaft 102 in acirculating manner. Referring to FIGS. 17A-17B, drive mechanism 1716 isa pulley system located within a housing 1750 located at proximal end104 of catheter shaft 102. Housing 1750 also houses a guide or divider1759 which guides drive belt 112 from catheter shaft 102 to a firstpulley 1754. A knob 1751 having a handle 1752 thereon is located outsidehousing 1750 such that an operator may manually control the pulleysystem. Knob 1751 has a centrally located hole 1753 which receives andis joined to a connector shaft 1756 extending from first pulley 1754.When an operator turns knob 1751 in a first direction via handle 1752,first pulley 1754 also turns in the first direction since first pulley1754 is fixedly connected to knob 1751 via connector shaft 1756. Byturning knob 1751, first pulley 1754 thus drives drive belt 112 and thecapture devices located thereon through catheter shaft 102 in acirculating manner.

In one embodiment of the present invention, the first pulley may bemodified to accommodate three-dimensional capture devices affixed todrive belt 112. For example, referring now to FIG. 29, a first pulley2954 may include a groove 2988 formed therein in order to accommodatethree-dimensional capture devices affixed to drive belt 112. The capturedevices may be basket or cage-like devices fixed to drive belt 112 asillustrated in FIGS. 5-10, 31, 33-34, and 38-39. Alternatively, thecapture devices may be interference devices fixed to drive belt 112 asillustrated in FIGS. 11, 32, and 35-37. These three-dimensional capturedevices may be formed of a compressible material as described above, andthus may compress in size when they are passed through the pulleysystem. Groove 2988 of first pulley 2954 will be of sufficient size toallow the three-dimensional capture devices to pass through the pulleysystem and thus circulate through catheter shaft 102.

In another embodiment, the drive mechanism may be an aspiration orvacuum source and/or a pressurization source at the proximal end of theobstruction removal system in order to advance drive belt 112 and thecapture devices located thereon through catheter shaft 102 in acirculating manner. Referring to FIGS. 47-48, drive mechanism 4716includes a hub 4771 located at the proximal end 4704 of catheter shaft4702. Hub 4771 includes a pressure port 4773 for receiving a source ofpressurization and a vacuum port 4775 for receiving a vacuum source.Catheter shaft 4702 may also include a vacuum shaft 4747 forming a clotparticle reservoir 4849 therein adjacent to proximal end 4704 ofcatheter shaft 4702. Clot particle reservoir 4849 is in fluidcommunication with second lumen 4824 of catheter shaft 4702. A source ofpressurization connected via pressure port 4773 pushes capture devices114 through first lumen 4820 and distal exit port 4808 of catheter shaft4702 as shown by directional arrows 4877 on FIG. 48. In the alternativeor in addition to, a vacuum source connected via vacuum port 4775 pullscapture devices 114 through second lumen 4824 of catheter shaft 4702 asshown by directional arrows 4879 on FIG. 48. The vacuum source alsoprovides a suction force along second lumen 4824 for pulling thecaptured clot particles proximally into clot particle reservoir 4849. Assuch, the vacuum source keeps second lumen 4824 free from clot particlesthat may dislodge from capture devices 114 as they travel through secondlumen 4824, thus keeping second lumen 4824 clear of debris orself-cleaning. Further, the vacuum source creates a negative pressure atthe distal reentry port 4810 of second lumen 4824 and thus may pull clotmaterial towards capture devices 114 thus facilitating the retrieval ofa small portion of the clot or obstruction in order to remove the sourceof vascular occlusion. The vacuum source may be any system capable ofproviding a negative pressure or suction force.

The source of pressurization may be any system capable of providing apressure force, and may, for example, be accomplished utilizing a fluidsuch as saline as shown in FIG. 49. The fluid may aid in the breakdownof the clot or obstruction 4928 in addition to the mechanical breakdownprovided by the capture devices. The fluid flow pushes capture devices3414 through first lumen 4920, distal exit port 4908, distal re-entryport 4910, and second lumen 4924 of catheter shaft 4902 as shown bydirectional arrows 4983 on FIG. 49 in order to advance drive belt 112and the capture devices located thereon through catheter shaft 4902 in acirculating manner. Although FIG. 49 has been described utilizingcapture devices 3414 described above in relation to FIG. 34, it will beapparent to those skilled in the art that the use of a fluid may beutilized with any embodiment described herein.

In another embodiment of the present invention, the drive mechanism maybe a mechanical double-pulley system manually operated by the deviceoperator which advances drive belt 112 and the capture devices locatedthereon through catheter shaft 102 in a circulating manner. Thedouble-pulley drive mechanism may include a loosening mechanism thatoperates similar to a cam device in order to create slack in the drivebelt, which may aid in capturing or interfering with the clot orobstruction. More particularly, FIGS. 20A-20B illustrate a drivemechanism 2016 including a first pulley 2070 and a second pulley 2072within a housing 2050 located at proximal end 104 of catheter shaft 102.Housing 2050 also houses a guide or divider 2059, which guides drivebelt 112 from catheter shaft 102 to the mechanical double-pulley system.A knob (not shown) is located outside housing 2050 such that an operatormay manually control the double-pulley system. The knob is connected tosecond pulley 2072. When an operator turns the knob in a first directionindicated by directional arrow 2076, second pulley 2072 also turns inthe first direction since second pulley 2072 is fixedly connected to theknob. A belt 2074 passes between first pulley 2070 and second pulley2072 in order to transmit the rotational motion created by the knob fromsecond pulley 2072 to first pulley 2070. By turning the knob, secondpulley 2072 causes first pulley 2070 to also rotate in the firstdirection via belt 2074. When first pulley 2070 rotates in the firstdirection, first pulley 2070 drives drive belt 112 and the capturedevices located thereon through catheter shaft 102 in a circulatingmanner.

Second pulley 2072 is an oblong shape, meaning that its diameter D1 iselongated in one direction. First pulley 2070 is a circular shape havinga diameter D2. As apparent from FIG. 20A, diameter D2 of first pulley2070 is less than elongated diameter D1 of second pulley 2072. Whensecond pulley 2072 is turned or rotated as described above, the oblongshape of second pulley 2072 creates slack in drive belt 112. Drive belt112 is taut over second pulley 2072 when drive belt 112 contactselongated diameter D1 of second pulley 2072 during its rotation as shownin FIG. 20A. However, drive belt 112 is loose, i.e., slack in drive belt112 is created, when second pulley 2072 rotates such that drive belt 112does not contact elongated diameter D1 of second pulley 2072 as shown inFIG. 20B. When drive belt 112 and the plurality of capture devices 114is an integral or one-piece conveyor or circulating element havingintegral curly, protuberant, or coiled sections formed by a wire elementthat also comprises the drive belt as described above in relation toFIGS. 12-15, the looseness or slack created in the integral or one-piececonveyor may improve the ability of the capture devices to capture orinterfere with the clot or obstruction. Since the slack releases tensionin the integral or one-piece conveyor, the slack allows recoil of thewire element in order to form the capture devices for effective clotcapture. The mechanical double-pulley system of FIGS. 20A-20B mayutilize any of cleaning mechanisms described herein to clean capturedclot particles from the drive belt and the capture devices locatedthereon as they pass through the proximal end of the obstruction removalsystem.

In another embodiment of the present invention, a loosening mechanismmay be utilized within the catheter shaft at the distal end thereof inorder to create a pre-defined amount of slack in the drive belt, whichmay aid in capturing or interfering with the clot or obstruction. Moreparticularly, FIG. 50 is a side sectional view of a distal portion 5006of a catheter shaft 5002 in accordance with another embodiment of thepresent invention. FIG. 50 illustrates a drive belt 5012 circulatingthrough a first lumen 5020 of catheter shaft 5002, exiting out of distalexit port 5008, returning into catheter shaft 5002 via distal re-entryport 5010, and through a second lumen 5024 of catheter shaft 5002. Drivebelt 5012 is illustrated in FIG. 50 without a plurality of capturedevices thereon for sake of clarity, but it is to be understood thatdrive belt 5012 carries a plurality of capture devices as describedherein through catheter shaft 5002 in a circulating manner. A gear 5085is located within catheter shaft 5002 on a middle portion 5099 ofcatheter shaft 5002. Middle portion 5099 of catheter shaft 5002 islocated between first lumen 5020 and second lumen 5024 of catheter shaft5002. Gear 5085 includes protrusions or teeth 5087 and drive belt 5012includes mating protrusions or teeth 5089. Teeth 5087 of gear 5085 areof such form, size, and spacing that they mesh or cooperate with teeth5089 of drive belt 5012. Due to the incremental spacing of teeth 5087,gear 5085 provides a means of moving drive belt 5012 in such a way thatthe exposed portion of drive belt 5012 (the portion of drive belt 5012extending outside of catheter shaft 102 between distal exit port 5008and distal reentry port 5010) has a pre-defined amount of slack. Thelooseness or slack created in drive belt 5012 may improve the ability ofthe capture devices to capture or interfere with the clot orobstruction. Since the slack releases tension in the exposed portion ofdrive belt 5012, the slack allows recoil of drive belt 5012 foreffective clot capture. A pulley system, such as for example that shownin FIGS. 17A-17B described above, may be utilized at the proximal end ofcatheter shaft 5002 for advancing drive belt 5012 through catheter shaft5002 in a circulating manner. When such a pulley system is utilized, theportion of drive belt 5012 located within second lumen 5024 is undertension (the active side of the loop) while the portion of drive belt5012 located within first lumen 5020 is not under tension (the passiveside of the loop). Operating the pulley system causes the portion ofdrive belt 5012 located within first lumen 5020 to advance through firstlumen 5020, causing gear 5085 to rotate at the same rate. Rotation ofgear 5085 maintains a pre-defined amount of slack in the exposed portionof drive belt 5012 as described above.

Another embodiment of the present invention is illustrated in FIGS.19A-19B in which a wire and capture devices thereon do not operate incirculating manner. In the embodiment shown in FIGS. 19A-19B, drivemechanism 1916 for passing a linear band 1964 through catheter shaft 102is a dual-spool arrangement. The dual-spool arrangement may be locatedwithin a housing 1950 located at the proximal end of catheter shaft 102.Housing 1950 also houses a guide or divider 1959 which guides band 1964from catheter shaft 102 to the dual-spool arrangement. The dual-spoolarrangement includes a first spool 1963 and a second spool 1966. A firstend 1965 of band 1964 is attached to first spool 1963, and a second end1967 of band 1964 is attached to second spool 1966. Band 1964 is wrappedaround first spool 1963 prior to usage such that there is no slack inband 1964 when it is located through the lumens of catheter shaft 102. Aknob 1951 having handle 1952 thereon is located outside housing 1950such that an operator may manually control the dual-spool arrangement.Knob 1951 is joined to a connector shaft 1968 extending from secondspool 1966. When an operator turns knob 1951 in a first direction viahandle 1952, second spool 1966 also turns in the first direction sincesecond spool 1966 is connected to knob 1951 via connector shaft 1968. Byturning knob 1951, second spool 1966 causes band 1964 to be advancedthrough catheter shaft 102. Band 1964 is collected or gathered aroundsecond spool 1966 as band 1964 is run through catheter shaft 102. Inthis embodiment, the captured clot particles do not have to be removedfrom band 1964 and the capture devices located thereon since band 1964operates in a non-circulating manner. However, if desired, a vacuum orfluid may be used to clean the captured clot particles from band 1964and the capture devices as they are wound onto second spool 1966. Theembodiment illustrated in FIGS. 19A-19B is preferably utilized whendrive belt 112 and the plurality of capture devices 114 is an integralor one-piece conveyor or circulating element having integral curly,protuberant, or coiled sections formed by a wire element that alsocomprises the drive belt as described above in relation to FIGS. 12-15.In addition, the embodiment illustrated in FIGS. 19A-19B may also beutilized with interference devices fixed to the drive belt as describedabove in relation to FIGS. 11, 32, and 35-57. These embodiments ofcapture devices are preferred since other three-dimensional designs forthe capture devices may get tangled together and make the dual-spoolarrangement nonfunctional.

Cleaning Mechanisms

Since the drive belt and the capture devices located thereon are driventhrough the catheter shaft in a circulating manner, the obstructionremoval system also includes one or more means of removing captured clotparticles from the capture devices so that the captured clot particlesdo not clog the obstruction removal system. In one embodiment of thepresent invention shown in FIG. 46, a vacuum shaft 4647 forming a clotparticle reservoir 4649 therein is provided at proximal portion 4604 ofcatheter shaft 4602. FIG. 46 is a sectional view of an obstructionremoval system 4600 in accordance with another embodiment of the presentinvention. Similar to the embodiment depicted in FIGS. 15-16, integralconveyor or circulating element 1513 is a wire element with a pluralityof capture devices comprised of integral random protuberant sections1548 formed therein. Integral conveyor or circulating element 1513 isformed of a material having superelastic or shape memory characteristicsas described above. The superelastic or shape memory characteristicsenable conveyor or circulating element 1513 to travel in a deformed,straightened state within a first lumen 4620 of catheter shaft 4602.When conveyor or circulating element 1513 exits distal end 4606 ofcatheter shaft 4602 via a distal exit port 4608, protuberant capturedevices 1548 may assume their “remembered” deployed or expandedconfiguration. Upon re-entry into catheter shaft 4602 via a distalreentry port 4610, conveyor or circulating element 1513 remains in itsprotuberant configuration as it travels through second lumen 4624 sothat the captured clot particles are retained in capture devices 1548.In order to ensure that loose clot particles do not migrate downstream,aspiration of second lumen 4624 is provided via a vacuum source 4669provided at the end of vacuum shaft 4647. Vacuum source 4669 provides asuction force along second lumen 4624 for pulling the captured clotparticles proximally into clot particle reservoir 4649. Clot particlereservoir 4649 is in fluid communication with second lumen 4624 ofcatheter shaft 4602. As such, vacuum source 4669 keeps second lumen 4624free from clot particles that may dislodge during the circulation ofconveyor or circulating element 1513 through second lumen 4624, thuskeeping second lumen 4624 clear of debris or self-cleaning. Further,vacuum source 4669 creates a negative pressure at the distal reentryport 4610 of second lumen 4624 and thus may pull clot material towardsconveyor or circulating element 1513 thus facilitating the retrieval ofa small portion of the clot or obstruction in order to remove the sourceof vascular occlusion in a bit-by-bit or piecemeal fashion. Vacuumsource 4669 may be any system capable of providing a negative pressureor suction force, including for example a syringe. At proximal portion4604 of catheter shaft 4602, catheter shaft 4602 includes a transitionsection 4627 for transitioning conveyor or circulating element 1513 fromsecond lumen 4624 into a drive mechanism 4616. Transition section 4627has a tapered shape in order to funnel conveyor or circulating element1513 from second lumen 4624 into drive mechanism 4616. Although FIG. 46has been described utilizing conveyor or circulating element 1513 withintegral random protuberant or curly sections 1548 formed therein, itwill be apparent to those skilled in the art that the vacuum shaft andresulting aspiration may be utilized with any embodiment describedherein.

In another embodiment, a vacuum and/or fluid may be utilized to cleancaptured clot particles from the drive belt and the capture deviceslocated thereon as they pass through the proximal end of the obstructionremoval system. A vacuum or aspirator that employs a suction force maybe applied at the proximal end of the obstruction removal system inorder to clean the captured clot particles from the drive belt and thecapture devices as they pass through the drive mechanism. Further, afluid under pressure may be applied at the proximal end of theobstruction removal system in order to clean the captured clot particlesfrom the drive belt and the capture devices as they pass through thedrive mechanism.

More particularly, as illustrated in FIG. 30, the drive mechanism may bea mechanical pulley system manually operated by the device operatorwhich advances drive belt 112 and the capture devices located thereonthrough catheter shaft 102 in a circulating manner. In the embodimentdepicted in FIG. 30, the capture devices are hairbrush-like interferencedevices 1133 described above with respect to FIG. 11. Drive mechanism3016 is a pulley system located within a housing 3050 located atproximal end 104 of catheter shaft 102. Housing 3050 also houses a guideor divider 3059 which guides drive belt 112 from catheter shaft 102through a vacuum chamber 3090 to a pulley 3054, and through a rinsechamber 3094. A knob 3051 having a handle 3052 thereon is locatedoutside housing 3050 such that an operator may manually control thepulley system. Knob 3051 has a centrally located hole (not shown) whichreceives and is joined to a connector shaft 3056 extending from pulley3054. When an operator turns knob 3051 in a first direction via handle3052, pulley 3054 also turns in the same direction since pulley 3054 isfixedly connected to knob 3051 via connector shaft 3056. By turning knob3051, pulley 3054 thus drives drive belt 112 and the hairbrush-likeinterference devices 1133 located thereon through catheter shaft 102 ina circulating manner. The hairbrush-like interference devices 1133 arepulled through the second lumen of catheter 102 and passes the guide ordivider 3059 in the vacuum chamber 3090, dislodging the clot particlesoff the hairbrush-like interference devices 1133 into the vacuum chamber3090. The hairbrush-like interference devices 1133 then pass through afirst one-way valve 3092 and around pulley 3054. Protrusions 1137located on drive belt 112 between the hairbrush-like interferencedevices 113 engage pulley 3054 and thus pull drive belt 112 at aconstant speed. The hairbrush-like interference devices 1133 then passthrough a second one-way valve 3093 in order to enter rinsing chamber3094. The hairbrush-like interference devices 1133 pass over or throughguide or divider 3059 while in rinsing chamber 3094 and then passthrough a third one-way valve 3097 in order to enter catheter shaft 102.

Vacuum chamber 3090 contains a connector or port 3091 for connection toa vacuum source (not shown). The vacuum source creates a vacuum in thevacuum chamber 3090 and in the second lumen of catheter 102. Thenegative pressure or vacuum keeps the second lumen free from clotparticles that may dislodge during the circulation of obstructionremoval system 100, thus keeping the second lumen clear of debris orself-cleaning. First one-way valve 3092 maintains the vacuum in thevacuum chamber 3090.

Rinse chamber 3094 contains a first connector or port 3095 and a secondconnector or port 3096 for circulating a rinsing fluid. First connector3095 is the fluid entry port and second connector 3096 is the fluid exitport. However, one of ordinary skill in the art will recognize that theconnectors may be interchanged such that first connector 3095 is thefluid exit port and second connector 3096 is the fluid entry port. Thehairbrush-like interference devices 1133 pass over or through the guideor divider 3059 in the rinsing chamber 3094 in order to ensure that thecaptured clot particles are removed from the hairbrush-like interferencedevices 1133 before the capture devices are re-circulated throughcatheter shaft 102. Drive belt 112 enters catheter shaft 102 throughthird one-way valve 3097 and into the first lumen of catheter shaft 102.One-way valves 3093 and 3097 prevent the fluid from exiting rinsingchamber 3094, except through fluid entry port 3095 and fluid exit port3096.

Another embodiment of a drive mechanism 1716 for removing captured clotparticles from the capture devices is shown in FIGS. 17A-17B. Drivemechanism 1716 includes a second collinear pulley 1757 that is providedto squeegee captured clot particles from the capture devices (notshown). First pulley 1754 includes protrusions or teeth 1755 and secondpulley 1757 includes mating protrusions or teeth 1758. Teeth 1755 offirst pulley 1754 are of such form, size, and spacing that they meshwith teeth 1758 of second pulley 1757. In other words, first pulley 1754and second pulley 1757 cooperate similar to two mating gears. Teeth 1755and 1758 of first and second pulleys 1754 and 1757, respectively, meshtogether at an intersection 1760. Teeth 1755 of first pulley 1754 meshwith teeth 1758 of second pulley 1757 in order to drive second pulley1758 in an opposite direction. Otherwise stated, when first pulley 1754is turned in a first direction via manually operated knob 1751, suchturning causes second pulley 1757 to turn in a separate oppositedirection. For example, if an operator turns knob 1751 and consequentlyfirst pulley 1754 in a clockwise direction, second pulley 1757 will turnin a counter clockwise direction. Further, teeth 1755 of first pulley1754 prevent slippage of second pulley 1757. As drive belt 112 and thecapture devices located thereon pass through intersection 1760, thecaptured clot particles located within the capture devices are pushed orsqueezed off drive belt 112 and into housing 1750. Additional cleaningmechanisms, such as a vacuum and/or fluid described above, may also beused to clean the captured clot particles from drive belt 112 and thecapture devices as they pass through the pulley system.

Another embodiment for removing captured clot particles from the capturedevices is shown in FIGS. 18A-18B. Drive mechanism 1816 is a singlepulley system. A single pulley 1854 functions similar to first pulley1754. A guide or divider 1859 guides drive belt 112 from catheter shaft102 to first pulley 1854. However, rather than a second collinearpulley, drive mechanism 1816 includes a brush 1861 that removes thecaptured clot from the capture devices prior to reaching single pulley1854. Brush 1861 includes a plurality of bristles 1862 that are attachedto the outside surface of divider 1859. Bristles 1862 extend fromdivider 1859 and may be formed of any suitable material, including butnot limited to PEBAX, nylon, polyimide, PEEK, polyethylene terephalate(PET) polyurethane, polyethylene, polypropylene, stainless steel, nickeltitanium, MP35N, and tantalum. As drive belt 112 and the capture deviceslocated thereon pass over brush 1861, the captured clot particleslocated within the capture devices are ensnared or caught in bristles1862. Additional cleaning mechanisms, such as a vacuum and/or fluiddescribed above, may also be used to clean the captured clot particlesfrom drive belt 112 and the capture devices as they pass through thesingle pulley system.

Additional Embodiments

Embodiments of the present invention have been described herein asincluding a single drive belt for carrying a plurality of capturedevices in a circulating manner through an obstruction removal system.However, more than one drive belt having a plurality of capture devicesthereon may be used to capture an obstruction. For example, FIG. 51 is aperspective view of a distal portion 5106 of a catheter shaft 5102. FIG.52 is a cross-sectional view of catheter shaft 5102, wherein the drivebelts and capture devices have not been shown for clarity. Cathetershaft 5102 has four parallel lumens extending there through forcirculating two drive belts, first drive belt 5112A and a second drivebelt 5112B, in a circulating manner through the obstruction removalsystem. First drive belt 5112A carrying capture devices 5114A extendthrough a first lumen 5220A of catheter shaft 5102, exit catheter shaft5102 via distal exit port 5108A, pass through a clot or obstructionwhile retrieving small particles of the obstruction, pull the capturedclot particles through distal reentry port 5110A, and extend through asecond lumen 5224A of catheter shaft 5102. Similarly, second drive belt5112B carrying capture devices 5114B extend through a first lumen 5220Bof catheter shaft 5102, exit catheter shaft 5102 via distal exit port5108B, pass through a clot or obstruction while retrieving smallparticles of the obstruction, pull the captured clot particles throughdistal reentry port 5110B, and extend through a second lumen 5224B ofcatheter shaft 5102. Utilizing multiple drive belts increase the numberof capture devices passing through the clot or obstruction, and thus mayassist in removing the entire mass of the clot or obstruction in arelatively shorter time. In addition, the multiple drive belts andcapture devices are parallel to each other and thus will evenly removethe side portions of the clot or obstruction. Capture devices 5114A offirst drive belt 5112A may encounter the clot or obstruction at the sametime as capture devices 5114B of second drive belt 5112B, as shown inthe side view of distal catheter portion 5106 in FIG. 53. Alternatively,as shown in FIG. 54, capture devices 5114A of first drive belt 5112A mayalternate with capture devices 5114B of second drive belt 5112B, suchthat the capture devices do not encounter the clot or obstruction at thesame time.

Another embodiment of the present invention including more than onedrive belt with a plurality of capture devices thereon is illustrated inFIGS. 55-56. FIG. 55 is a side view of a distal portion 5506 of acatheter shaft 5502. FIG. 56 is a cross-sectional view of catheter shaft5502, wherein the drive belts and capture devices have not been shownfor clarity. Catheter shaft 5502 has four parallel lumens extendingthere through for circulating two drive belts, first drive belt 5512Aand a second drive belt 5512B, in a circulating manner through theobstruction removal system. Rather than extending parallel to each otheras shown in the embodiment of FIGS. 51-54, drive belts 5512A and 5512Bexit the distal portion 5506 in a crossing or overlapping pattern. Forexample, first drive belt 5512A is shown as extending over a “vertical”path when it exits catheter shaft 5502 while second drive belt 5512B isshown as extending over a “horizontal” path when it exits catheter shaft5502. First drive belt 5512A carrying capture devices 5514A extendthrough a first lumen 5620A of catheter shaft 5502, exit catheter shaft5502 via a distal exit port (not shown), pass through a clot orobstruction while retrieving small particles of the obstruction, pullthe captured clot particles through a distal reentry port (not shown),and extend through a second lumen 5624A of catheter shaft 5502.Similarly, second drive belt 5512B carrying capture devices 5514B extendthrough a first lumen 5620B of catheter shaft 5502, exit catheter shaft5502 via a distal exit port (not shown), pass through a clot orobstruction while retrieving small particles of the obstruction, pullthe captured clot particles through a distal reentry port (not shown),and extend through a second lumen 5624B of catheter shaft 5502. In thisembodiment, the multiple drive belts and capture devices areperpendicular to each other and thus will evenly remove the clot orobstruction.

While various embodiments according to the present invention have beendescribed above, it should be understood that they have been presentedby way of illustration and example only, and not limitation. It will beapparent to persons skilled in the relevant art that various changes inform and detail can be made therein without departing from the spiritand scope of the invention. Thus, the breadth and scope of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the appendedclaims and their equivalents. It will also be understood that eachfeature of each embodiment discussed herein, and of each reference citedherein, can be used in combination with the features of any otherembodiment. All patents and publications discussed herein areincorporated by reference herein in their entirety.

1. A system for removing an obstruction within a body lumen, the systemcomprising: a catheter shaft having a proximal end and a distal end, thecatheter shaft defining a first lumen having a distal exit port and asecond lumen having a distal reentry port, wherein the first and secondlumens extend side-by-side from the proximal end to the distal end ofthe catheter shaft; and a drive belt, wherein the drive belt is disposedwithin the catheter shaft in a circulating manner through the firstlumen, the distal exit port, the distal reentry port and the secondlumen, wherein the drive belt has integral sections forming a pluralityof capture devices thereon for removing the obstruction from the bodylumen when the drive belt is circulated through the catheter shaft, suchthat each capture device is capable of removing at least a portion ofthe obstruction as the capture device travels between the distal exitport and the distal reentry port of the catheter shaft.
 2. The system ofclaim 1, wherein the capture devices are selected from a groupconsisting of coiled and protuberant integral sections.
 3. The system ofclaim 1, wherein the drive belt is a wire constructed out of an elasticor shape memory material such that the drive belt has a firststraightened configuration and a second expanded configuration formingthe plurality of capture devices.
 4. The system of claim 3, wherein thefirst lumen is smaller in size than the second lumen.
 5. The system ofclaim 1, further comprising: a second drive belt having a secondplurality of capture devices located thereon, wherein the second drivebelt is disposed within the catheter shaft in a circulating mannerthrough a third lumen having a distal exit port and a fourth lumenhaving a distal reentry port, wherein the third lumen and the fourthlumen extend side-by-side from the proximal end to the distal end of thecatheter shaft.
 6. A system for removing an obstruction within a bodylumen, the system comprising: a catheter shaft having a proximal end anda distal end, the catheter shaft defining a first lumen having a distalexit port and a second lumen having a distal reentry port, wherein thefirst and second lumens extend side-by-side from the proximal to distalend of the catheter shaft; a drive belt, wherein the drive belt isdisposed within the catheter shaft in a circulating manner through thefirst lumen, the distal exit port, the distal reentry port and thesecond lumen; and a plurality of capture devices attached to the drivebelt for removing the obstruction from the body lumen when the drivebelt is circulated through the catheter shaft, such that each capturedevice is capable of removing at least a portion of the obstruction asthe capture device travels between the distal exit port and the distalreentry port of the catheter shaft.
 7. The system of claim 6, whereinthe plurality of capture devices are a plurality of basket-like devicesfixed to the drive belt.
 8. The system of claim 7, wherein each of theplurality of basket-like devices has a shape selected from a groupconsisting of a cylinder, a sphere, a bowl, an elongated oval, acrescent, and a spool having flared end portions.
 9. The system of claim7, wherein the plurality of capture devices include strands that extendparallel to the drive belt and parallel to blood flow when locatedwithin the body lumen.
 10. The system of claim 7, wherein the pluralityof capture devices are formed from a mesh material.
 11. The system ofclaim 6, wherein the plurality of capture devices are a plurality ofinterference devices fixed to the drive belt, each of the plurality ofinterference devices selected from a group consisting of ahairbrush-like device having radially extending bristles and awire-brush device having looping strands.
 12. The system of claim 6,wherein the plurality of capture devices are a plurality of interferencedevices fixed to the drive belt, each of the plurality of interferencedevices selected from a group consisting of a bead-like device, aballoon-like device, and a burr-like device.
 13. The system of claim 6,further comprising: a second drive belt having a second plurality ofcapture devices located thereon, wherein the second drive belt isdisposed within the catheter shaft in a circulating manner through athird lumen having a distal exit port and a fourth lumen having a distalreentry port, wherein the third lumen and the fourth lumen extendside-by-side from the proximal to distal end of the catheter shaft. 14.A method for removing an obstruction within a body lumen, the methodcomprising the steps of: positioning an obstruction removal system nearthe obstruction within the body lumen, wherein the obstruction removalsystem includes a catheter shaft having a proximal end and a distal end,the catheter shaft defining a first lumen having a distal exit port anda second lumen having a distal reentry port, wherein the first lumen andthe second lumen extend side-by-side from the proximal end to the distalend of the catheter shaft, a drive belt, and a plurality of capturedevices occurring along at least a portion of the drive belt;circulating the drive belt though the catheter shaft such that theplurality of capture devices are advanced through the first lumen,through the distal exit port, through the distal reentry port andthrough the second lumen; removing at least a portion of the obstructionfrom the body lumen in a bit-by-bit fashion as each capture devicetravels between the distal exit port and the distal reentry port of thecatheter shaft; and removing the entire obstruction from the body lumenafter the plurality of capture devices are circulated through thecatheter shaft in a series of passes.
 15. The method of claim 14,wherein the plurality of capture devices are formed by integral sectionsof the drive belt, the integral sections being selected from a groupconsisting of coiled and protuberant.
 16. The method of claim 15,wherein the drive belt is a wire constructed out of an elastic or shapememory material such that the drive belt has a first straightenedconfiguration and a second expanded configuration forming the pluralityof capture devices.
 17. The method of claim 14, wherein the plurality ofcapture devices are a plurality of basket-like devices attached to thedrive belt.
 18. The method of claim 17, wherein each of the plurality ofbasket-like devices has a shape selected from a group consisting of acylinder, a sphere, a bowl, an elongated oval, a crescent, and a spoolhaving flared end portions.
 19. The method of claim 14, wherein theplurality of capture devices are a plurality of interference devicesattached to the drive belt, each of the plurality of interferencedevices selected from a group consisting of a bead-like device, aballoon-like device, and a burr-like device.
 20. The method of claim 14,wherein the plurality of capture devices are a plurality of interferencedevices attached to the drive belt, each of the plurality ofinterference devices selected from a group consisting of ahairbrush-like device having radially extending bristles and awire-brush device having looping strands.